高速公路既有高边坡二次开挖稳定性及施工方法研究

Study on Stability and Construction Method of High-slope Excavation

针对高速公路边坡二次开挖过程中易出现结构裂纹、变形,失效等问题,以某高速公路改扩建工程项目为对象,采用FLAC 3D软件来模拟高边坡二次开挖中结构的应变-应力特征。研究结果表明:原始道路边坡初始应力与边坡外形保持一致,表现出典型的分区现象。边坡二次开挖坡脚出现的剪应力集中和扩展,在新开挖坡面出现的剪应力集中,造成结构面两侧应力突变,影响结构稳定性。开挖面附近边坡拉应力方向发生改变,而远离开挖坡面区结构体主应力方向并未变化,最大压应力方向的改变只出现在开挖坡脚附近,坡体内部受应力影响作用相对较小。

In view of the secondary highway slope excavation process easy occurrence structure crack,deformation,failure and other issues,to a certain highway reconstruction project as the object,using FLAC 3d software to simulate the high slope of the secondary excavation in the strain-stress characteristics of the structure.The results show that the initial stress of the original road slope is consistent with the shape of the slope,and the typical partition phenomenon is shown.The shear stress concentration and extension in the slope of the second excavation slope of the slope are concentrated in the new excavation slope,resulting in the stress mutation on both sides of the structural plane,affecting the structural stability.Slope excavation near surface tensile stress direction change,and move away from the excavation slope structure principal stress direction does not change,only change in the direction of maximum compressive stress appears near the excavation slope toe,slope internal stress influence function is relatively small.